The condition is being reported in accordance with 10 CFR 50.73(a)(2)(v)(C) as an event or condition that could have prevented fulfillment of a safety function.

The cause of the event was the failure of the ASCO solenoid valve. Based on further review, the ASCO solenoid valve has been determined to be less than adequate for its application in Reactor Building HVAC.

There were no actual consequences to the health and safety of the public as a result of this event.

comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov. and to the Desk Officer, Office of Information and Regulatory Affairs.

NEON-10202, (3150-0104), Office of Management and Budget. Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number. the NRC may not conduct or sponsor, and a person is not required to respond lo, the information collection.

i YEAR 2017 - 005 - 00

Contents

CONDITIONS PRIOR TO EVENT

Unit 1 — Mode 1, approximately 100 percent Rated Thermal Power Unit 2 — Mode 1, approximately 100 percent Rated Thermal Power There were no structures, systems, or components that were inoperable at the start of the event that contributed to the event.

The cause of the trip was due to a failed solenoid valve [EIIS Code: SOL] on the discharge damper [EIIS Code: DMP]. Upon failure of the solenoid valve, the discharge damper failed closed and Filtered Exhaust System Fan A tripped on low flow.

CAUSE OF EVENT

The cause of the event was the failure of the ASCO solenoid valve. Based on further review, the ASCO solenoid valve has been determined to be less than adequate for its application in Reactor Building HVAC.

Based on engineering analysis of the event, secondary containment could have performed its safety function of isolating as assumed in the accident analysis and of re-establishing 0.25 in w.g. vacuum (drawdown) within the assumed accident analysis time (10 minutes).

This event will not be counted as a safety system functional failure (SSFF) for the NRC performance indicator based on the engineering analysis supporting the system's ability to fulfill the safety function.

comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, 'Washington, DC 20555-0001, or by e-mail to NEOB-10202, (3150-0104). Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. LER NUMBER

NO Susquehanna Steam Electric Station Unit 2 05000388

CORRECTIVE ACTIONS

Key corrective actions include replacement of the failed solenoid valve with a more robust model.